Lock-End Extension Spring 28 in Steel with Safety Containment Rod

  • The E900 HARDWRARE SL728 28 in. Lock-End Extension Spring is a Holmes spring replacement for most one-piece garage doors. 2 x SL728 springs can handle up to a 150 lb. door while 4 x SL728 springs can handle up to 300 lbs.. SL728 springs are also a popular installment for lifting toy hauler doors.